A study published late last year by researchers at the University of Gottingen in Germany showed strawberries pollinated by bees are larger, longer-lasting and tastier than their wind-pollinated or self-fertile counterparts.
A team led by Bjorn Kurtt compared the difference between strawberry crops pollinated by wild populations of bumble bees with wind or self-pollinated plants. On average, strawbs pollinated by bees were 11% heavier than wind-pollinated fruit and 33.3% larger than self-pollinated ones. The colour of the fruit was much more vibrant and there were few runty, malformed ones, the result of partial fertilisation.
Bee-pollinated fruit was also much firmer and had a better shelf life, staying fresh and sweet much longer. After being stored for four days, none of the self-pollinated strawberries were marketable and 29% of wind-pollinated ones could be sold, but 40% of bee-pollinated fruit was still viable. So, get bees working for you if you can't eat all your fresh strawberries immediately.
The report says bumble bees give you more strawberries as well as larger, tastier ones. Bee-pollinated plants produce 26% more fruits than wind-pollinated ones and 62% more than self-pollinated strawberries. This is another incontestable reason for having bumble bees in your garden.
Luring bumble bees to the garden is a straightforward task - all they require is a steady supply of food and shelter. Provided the garden isn't painfully neat and tidy, there will always be a comfy nook for a nest - a dry spot away from direct sunlight; a hole previously occupied by mice or voles; a dryish bank; or a billet beneath a hedge.
When bees emerge after hibernation, they need a quick nectar fix. Shrubs such as mahonia or flowering currant suit them, as do early-flowering wallflowers and aubretia.
Bees feed on most flowers but won't touch bedding plants that have little or no scent. Showy doubles are also useless. The double whorls of petals have been bred to replace the male and female parts of the flower and the nectaries are very small or non-existent.
Bee species have different techniques for harvesting the all-important sugary nectar. Some species, like Bombus hortorum, have long tongues and are drawn to tubular flowers such as lonicera, pulmonaria or nepeta. Others, such as Bombus pratorum, have short tongues and need open-topped species like verbenas or hardy geraniums.
Throughout the summer, ensure there's a succession of single, open, nectar-rich flowers; all kinds of foxglove are popular with many bumblebees. Single roses can even provide a pollen bath for bumblebees, as they seem to wallow among the stamens. All types of cornflowers are easy to grow and make a good show in the garden as well as having lots of nectar. Eryngiums are very popular and lavenders is a classic.
To be sure of next year's army of pollinators, keep bee-friendly flowers going as long as possible. The queens need to build up their reserves before hibernating. Late-flowering sedums are useful, as are Michaelmas daisies and Japanese anemones. If you have space and height, let ivy grow tall and flower in early winter.
Two other useful pollinators Kurtt's study - published in The Proceedings Of The Royal Society - didn't cover are queen wasps for early season and hoverflies for mid to late season. Wasps emerge at much the same time as bumbles and work on early gooseberries and currants: they also perform an invaluable task on my greenhouse loganberry. With their short tongues, hoverflies need flat flower heads. Flowering herbs such as dill, coriander and fennel are excellent. Fashionable umbellifers such as Orlaya grandiflora are also ideal.